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本帖最后由 passagere 于 2017-6-29 05:25 编辑
: e S" r3 G% _4 G. ^: G+ Bsheleason 发表于 2017-6-27 18:12 - x- a0 `* c% ]! X) v# b' @
借楼问一下。有款灯具 输入线是3线 里面连接的内置电源。灯具外壳是金属 但是外壳没有接地。
, O! F0 e, E2 d( R。灯具的输入 ...
) ~7 w' ~' d7 {: e, L按60598,地线没有连接到可接触的金属部件上时,可以作为II类灯具(同时满足II类结构要求)。II类灯具不需要做接地连续性测试。GND到地线上不传导绝缘失效时的危险电流,所以不需要做。, T8 I: F' K+ e3 m
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GND上到地线,是为了功能或者电磁兼容的作用,不是为了传播电流的。如果I类灯具,且PCB上的铜箔作为传输路径时(I类灯具上也有功能接地部分,不是接到PCB上就一定对trace有大电流传播要求),那是需要额外验证大电流通过能力的。路径为:地线——PCB trace——可能带电的金属部件时,trace才可能传播大电流。
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% C! s) z$ P# a在60598里找到条款,按II类灯具判就可以了。
) D3 T @2 R5 Y! b2 ]1.2.238 K* n7 j) X& M0 P' Q# T
class II luminaire
" G7 w \, }$ s# B' |8 g* G) f9 f" Kluminaire in which protection against electric shock does not rely on basic insulation only, but in
) ~! ?: C" E2 `2 |, {; n, N8 c1 wwhich additional safety precautions such as double insulation or reinforced insulation are/ j1 v* d) Q! t
provided, there being no provision for protective earthing or reliance upon installation
% d) z' k% Y4 T9 sconditions
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5 m& B) t7 t. d/ H: E+ T' z0 v: ONote 3 to entry: If earthing is provided to assist starting, or for EMC reasons, but is not connected to an. X# {4 G) v! a- Y6 f
accessible metal part, the luminaire may still be deemed to be of class II. Accessible metal parts in compliance with
) y0 ]0 \7 T2 d. _+ |9 Q R: Bthe appropriate IEC lamp specification and other metal parts not normally earthed and not normally accessible
) [4 K1 [* V* h0 X* L8 Zduring normal use are not regarded to be conductive parts which may cause an electric shock unless the tests of
' g7 U0 }( c0 |. F; `2 v/ MAnnex A show them to be live parts.- h+ X7 \7 @# `( H3 B% t
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从上面条款可以看出,功能接地的灯具,满足要求时可以判为I类灯具。具体判定位I还是II,看结构特点和那个更容易实现、简单。8 Z3 Q( \- O8 \8 @8 i
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